Considering that U.S. President Donald Trump and German Chancellor Angela Merkel are known for their frosty relationship, one major political voice in Germany called for a rapprochement between two of the world's biggest economies.

"What (Germany) shouldn't do is take an anti-American course," Ralf Stegner, deputy leader of the center-left Social Democratic Party (SPD), told CNBC's Squawk Box Monday.

"We should never forget that relations with the United States are very important for us," Stegner warned. "(The U.S.) will survive a Trump presidency, definitely," he added.

"Donald Trump does a lot of things that are very worrisome for Europe, and that even makes the nationalistic developments we have within Europe stronger," Stegner said, adding that SPD Chairman and chancellery candidate Martin Schulz's track record as a strong leader would mitigate this.

Schulz served as president of the European Parliament between 2012-17. He did not stand for re-election at the start of this year to concentrate instead on German domestic politics.

Stegner cast doubt over Merkel's chances of winning a fourth term in the Bundestag. "(I) don't think that Angela Merkel will have it as easy as the last two times," he said, attributing this to her not being forthcoming on the subjects of taxes and pensions, among others. Merkel "is experienced and she was successful but she doesn't have many ideas left for the future," he added.

The SPD is attempting to win back voters by focusing its campaign on social issues. It wants to raise taxes on the rich and catalyze spending on education and infrastructure.

Casting doubt on Merkel's potential success when Germans head to the polls in September, Stegner said that the chancellor "doesn't say very much … (but) in Germany, many voters will expect that a German leader would say to say Donald Trump, 'Certain developments won't go with us.'"